JPH03108532A - Copper-clad laminate - Google Patents

Abstract

PURPOSE:To form a conductive path in an insulating layer without plating by disposing a copper foil to a metallic piece fitted into a through-hole shaped to the insulating layer and the surface of the insulating layer through a conductive layer. CONSTITUTION:A copper-clad laminate is composed of a through-hole 3 formed to an insulating layer l and a metallic piece 4 fitted into the through-hole 3, and a copper foil 2 is arranged to the metallic piece 4 fitted into the through- hole 3 of the insulating layer 1 and the surface of the insulating layer 1 by utilizing the adhesive properties of a conductive layer 5 through the conductive layer shaped by curing adhesives having conductivity. A conductive path can be formed in the insulating layer 1 of the copper-clad laminate without plating by using such a copper-clad laminate, and a printed wiring board can be manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a copper-clad laminate used for printed wiring boards.

[Conventional technology]

When forming a circuit on a copper-clad laminate formed by arranging copper foil on the surface of an insulating layer to form a printed wiring board, the conventional method for forming conductive paths in the insulating layer is as shown in FIG. As shown, copper foil 2 is disposed on both surfaces of an insulating layer 1, and a hole 3 is formed through the copper foil 2 and the insulating layer 1, and then through-hole plating is performed to form a conductive path 9 by electroless plating and electroplating. law is commonly practiced. However, when the aspect ratio of the depth/diameter of the through hole is large or the hole is not penetrated, forming a plating layer that serves as a conductive path on the inner wall of these holes is difficult to ensure uniform wetting of the plating solution. In some cases, the plating does not adhere to the inner wall of the hole and a conductive path made of the plating layer is not formed due to difficulties in sufficiently rinsing the processing solution with water. Further, according to the above-mentioned through-hole plating method, copper plating is also performed on the surface of the copper foil, which increases the thickness of the copper foil, making it particularly difficult to form fine circuits. Additionally, even if a single-sided wiring pattern is sufficient, it is often necessary to use a double-sided copper-clad laminate to form a conductive path in the through hole, resulting in a very expensive product. .

[Problem to be solved by the invention]

An object of the present invention is to provide a copper-clad laminate that can be used as a printed wiring board by forming conductive paths within the insulating layer of the copper-clad laminate without plating.

[Means to solve the problem]

In order to solve the above problems, the copper-clad laminate according to the present invention includes a through hole formed in an insulating layer, a metal piece fitted into the through hole, and a conductive layer on the surfaces of the metal piece and the insulating layer. An object of the present invention is to provide a copper-clad laminate characterized in that a copper foil is disposed therebetween.

〔Example〕

A detailed explanation will be given below based on the drawings. FIG. 1 is a sectional view of a copper-clad laminate according to an embodiment of the present invention. This copper-clad laminate has the following configuration.

It consists of a through hole 3 formed in the insulating layer 1 and a metal piece 4 fitted into the through hole 3.
A copper foil 2 is disposed on the surface of the metal piece 4 fitted to the metal piece 4 and the insulating layer 1, using the adhesive property of the conductive layer 5, which is made of a hardened conductive adhesive. . Since the through hole 3 is drilled, it generally has a circular cross section, but it may also be oval, square, etc. To fit the metal piece 4, either the through hole 3 or the metal piece 4, or both. An adhesive may or may not be used.

Note that FIG. 2 shows a copper-clad laminate of another embodiment in which IR foils 2 are disposed on both surfaces with conductive layers 5 interposed therebetween. Further, FIG. 3 shows an example of the use of the copper-clad laminate of the present invention in which a through-hole 6 having a circular cross section is formed inside the metal piece 4 of the copper-clad laminate of FIG.
FIG. 4 shows another example of use similar to that of FIG. 1 in which a non-through hole 7 with a circular cross section is formed inside the metal piece of the copper-clad laminate. Since the metal piece 4 is fitted into the insulating layer 1, a hole of any size can be formed as long as it is a through hole 6 or a non-through hole 7 that is within the cross section of the metal piece 4. The hole wall of this through hole or non-through hole, that is, the metal piece 4 remaining in the through hole of the insulating layer 1
itself becomes a conductive path, and the surface ii t is passed through the conductive layer 5.
A printed wiring board electrically connected to ri 2 is obtained.

In this way, in the copper-clad laminate of the present invention, the through holes are drilled in the copper piece fitted into the through holes in the insulating layer, and the copper pieces remaining in the through holes in the insulating layer are used as conductive paths having the through holes. Therefore, problems that arise when forming a conductive path in a through hole in an insulating layer by electroless plating or electroplating, when the aspect ratio of the depth/diameter of the through hole is large or when the hole is not penetrated,
The plating does not adhere to the inner wall of the hole and no conductive path is formed. (2) Copper plating is also applied to the surface of the copper foil, increasing the thickness of the W4 foil, making it particularly difficult to form fine circuits. ■Even if a single-sided wiring pattern is sufficient, it is often necessary to use a double-sided copper-clad laminate to form a conductive path in the through hole, which is extremely expensive. That is, it is possible to obtain a printed wiring board in which the metal piece directly becomes a conductive path having through holes and non-through holes and is connected to the copper foil on the surface. In addition, since electroless plating and electroplating are not applied to through holes and non-through holes, the thickness of the copper foil on the surface of the copper clad laminate remains constant, and through holes and non-through holes that serve as conductive paths are not plated. Since it can be processed into a printed wiring board, it is possible to form a fine circuit with a narrow circuit width corresponding to the initial thickness of the copper foil. Furthermore, it is also possible to easily create conductive paths within the insulating layer even with a single-sided copper-clad laminate without requiring copper foil on both surfaces of the insulating layer, which is the core of plating.

In addition, a metal piece that is fitted into a through hole in an insulating layer and has a through hole or a non-through hole is also effective as a heat dissipation body, and is used especially for copper for printed wiring boards in fields where heat dissipation is required. It is also useful as a tension laminate.

Next, the materials used for the copper-clad laminate of the present invention will be described.

As the insulating layer 1 constituting the copper-clad laminate shown in FIGS. 1 and 2, an insulating material obtained by curing the resin of a prepreg obtained by impregnating a base material with a resin and drying is used. Here, the resin for the insulating layer 1 is epoxy resin, polyimide resin, fluorine resin, phenol resin, unsaturated polyester resin, PPO.
Resins such as resins and modified resins thereof are suitable.

Note that as the base material for the insulating layer 1, paper, cloth, glass fiber, synthetic resin fiber, etc. can be used as appropriate depending on the purpose. In particular, inorganic materials such as glass fiber are heat resistant,
It is preferred because of its excellent moisture resistance.

The metal piece 4 fitted into the through hole 3 of the insulating layer 1 can be appropriately selected from copper, brass, aluminum, iron, stainless steel, etc. Among them, copper is particularly preferred because of its excellent electrical conductivity and thermal conductivity.

The conductive layer 5 is made of epoxy resin, polyimide resin, phenol resin, unsaturated polyester resin, PP containing metal powder with excellent conductivity such as gold, silver, copper, or aluminum.
A conductive material made of a resin composition such as O resin and modified resins thereof is used. It is preferable to use the same resin as the resin for the insulating layer 1 because it has strong adhesive properties, dimensional changes are consistent, and warping is less likely to occur.

〔Effect of the invention〕

By using the copper-clad laminate of the present invention, conductive paths can be formed within the insulating layer of the copper-clad laminate without plating, and a printed wiring board can be formed.

[Brief explanation of drawings]

Figure 1 is a sectional view of one embodiment of the present invention, Figure 2 is a sectional view of another embodiment, Figures 3 and 4 are different usage examples of Figure 1, and Figure 5 is one usage of the conventional example. A cross-sectional view of each example is shown. 1... Insulating layer 2... Copper foil 3... Through hole 4... Metal piece 5... Conductive layer Fig. 3 2 Fig. 4

Claims (1)

[Claims] (1) A through hole formed in an insulating layer, a metal piece fitted into the through hole, and a copper foil disposed between the metal piece and the surface of the insulating layer via a conductive layer. Copper-clad laminate.